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Single Screen RLE Decoding on NES


TylerBarnes
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So I'm working on learning more about the NES and at the same time like talking about what I'm working on. In this case it's compression for a single screen.  Made this as a sort of 'get my thoughts in order' video to help myself learn. As well as, I hope someone else at the same sort of level of learning as I am could get some help from it. Furthermore, I am also hoping that by talking about what I am doing, I could get corrected by more experienced coders if I'm doing stuff poorly. I plan on making more regarding decoding uncompressed strings and special cases. 
 

 

Edited by TylerBarnes
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Ooooh RLE is a good first compression scheme. You can then try making it fancy 😉 

I did one where a 3-bit value selects either one of the 6 most common tiles, another tile, or raw data, and the 5 remaining bits determine the length of the data to copy. Tho I think I added something to make it possible for the game to write 64 bytes at once instead of the maximum of 32 in a 5-bit value

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  • 1 month later...
21 hours ago, Kiro_RCR_ said:

What did you use for the encoder? Did you write your own c++/python encoder or use something else? I'm looking for a tool that can do it before I set about writing my own encoder in c++.

I wrote my own encoder in 6502 assembly. It is an NES rom that take a single screen .nam file and stores the encoded hex in RAM. I unfortunately don't know any other programming languages. 

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  • 2 weeks later...
On 2/6/2020 at 6:36 PM, TylerBarnes said:

I wrote my own encoder in 6502 assembly. It is an NES rom that take a single screen .nam file and stores the encoded hex in RAM. I unfortunately don't know any other programming languages. 

Now that's something. Writing your NESDev tools to run on the NES itself. Awesome.

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